The present application relates generally to a seal assembly for turbo-machinery and more particularly relates to a film riding seal assembly for facilitating sealing in the turbo-machinery.
Various types of turbo-machinery, such as, gas turbine engines, aircraft engines, and steam turbines are known and widely used for applications including power generation, propulsion, and the like. The efficiency of the turbo-machinery depends in part on clearances between the internal components of the turbo-machinery and the leakage of fluids through such clearances. For example, large clearances may be intentionally allowed at certain rotor-stator interfaces to accommodate large, thermally or mechanically-induced relative motions. Leakage of fluid through these clearances from regions of high pressure to regions of low pressure may reduce the efficiency of the turbo-machinery.
Different types of seal assemblies are used to minimize the leakage of the fluid flowing through various clearances in the turbo-machinery. The seal assemblies, however, are often subject to relatively high temperatures, thermal gradients, and thermal and mechanical expansion and contraction during various operational stages that may increase or decrease the clearance therethrough. For example, traditional labyrinth sealing assemblies are assembled to aid very tight clearance during a start-up transient phase. Use of such traditional labyrinth sealing assembly may lead to large clearances during a steady state operation, thereby leading to poor performance in the steady state operation. Moreover, such a tight sealing caused by the traditional labyrinth sealing assemblies in the start-up transient phase may also result in rubbing of the labyrinth sealing assemblies. Whereas, the labyrinth sealing assemblies arranged with large radial clearances (to avoid seals rubs) lead to increased leakage.
There is therefore a desire for improved compliant sealing assemblies for use with the turbo-machinery.